1. The Field of the Invention
The present invention is directed generally to an anastomosis apparatus for use in intraluminally directed vascular anastomosis. More specifically the present invention is directed to an apparatus for attaching, and in particular for stapling, an end of a graft vessel to a wall of a blood vessel.
2. Relevant Technology
An endoscope is an instrument for the examination of the interior of a canal or hollow viscus. Most endoscopic procedures operate according to passive techniques, namely exploring and diagnosing. However, some endoscopic procedures have evolved so that they operate according to active or interventional procedures. In addition to exploring and diagnosing, active endoscopic procedures perform corrective tasks such as therapeutic and/or surgical tasks.
Active endoscopic procedures are highly effective because of a plurality of reasons. These reasons include: (a) minimal invasion of the patient's body; (b) reduced requirements of medical facilities and medical skill, and (c) quasi-simultaneity, if so desired, of the exploration, diagnosis, and corrective tasks.
For example, in merely a few hours, an active endoscopic technique such as a colonoscopy permits the exploration of the entire colon and rectum, the recording of selected images, the localization of abnormalities such as intestinal polyps, the removal of any polyp, and the extraction of any polyp for additional examination. If the colonoscopy had not been performed and any existing polyp had been left attached to the intestinal wall, such polyp might have become a malignant tumor thus giving rise to a perhaps lethal colorectal cancer. Such a colonoscopy is performed without the administration of general anesthesia. Furthermore, it is performed by a team that involves only a few health practitioners who do not necessarily have to be trained in the techniques that are required in surgical or other more invasive procedures.
The preceding characterization of active endoscopic procedures and the accompanying illustrative example aid in explaining why active endoscopic procedures enjoy great acceptance. This is because active endoscopic procedures lead to considerable savings in time and resources, they are minimally invasive, they can be repeatedly applied with minimal risk of undesirable side effects, and the corrective action may provide preventive effects that would otherwise be hard or even impossible to accomplish.
The foregoing description and characterization of active endoscopic procedures is intended to encompass the characteristics and advantages of peripheral techniques that do not necessarily require the use of an endoscope. Endoscopic applications are generally used in intracavity procedures such as intrathoracic and intraabdominal procedures. Peripheral techniques are usually employed in other body regions, such as arms and legs.
In short, it is a desirable goal to be able to provide by active endoscopic or peripheral procedures a variety of medical services that are currently provided by techniques that are more invasive and more demanding in time and in medical resources and skills. This goal is justified by the efficiency, effectiveness, safety, low cost, and preventive accomplishments of active endoscopic or peripheral procedures. In particular, this invention provides new methods and systems for performing vascular anastomoses by intraluminally directed active endoscopic or peripheral procedures. The intraluminally directed or intravascular part of the procedures of this invention is based on an examination performed by, for example, fluoroscopy, and extraluminal manipulation is performed endoscopically or according to a peripheral technique.
One aspect of this invention encompasses the quasi-simultaneity of the exploration, diagnosis and corrective tasks that can be achieved in vascular anastomoses performed by the intraluminally directed active endoscopic or peripheral procedures of this invention. Another aspect of this invention includes the minimally invasive character of the vascular anastomoses that are performed by the active endoscopic or peripheral procedures of this invention. These procedures are also characterized by comparatively reduced requirements of medical facilities and skill. To more effectively describe and enable the present invention, a review of some basic terminology and related technology is offered in the immediately following subsections.
2.1. Terminology
An anastomosis is an operative union of two hollow or tubular structures. Anastomotic structures can be part of a variety of systems, such as the vascular system, the digestive system or the genitourinary system. For example, blood is shunted from an artery to a vein in an arteriovenous anastomosis, and from the right pulmonary artery to the superior vena cava in a cavopulmonary anastomosis. In other examples, afferent and efferent loops of jejunum are joined in a Braun's anastomosis after gastroenteroscopy; the ureter and the Fallopian tube are joined in a ureterotubal anastomosis, and the ureter and a segment of the sigmoid colon are joined in a ureterosigmoid anastomosis. In microvascular anastomosis, very small blood vessels are anastomosed usually under surgical microscope.
An anastomosis is termed end-to-end when the terminal portions of tubular structures are anastomosed, and it is termed end-to-side when the terminal portion of a tubular structure is anastomosed to a lateral portion of another tubular or hollow structure. In an end-to-side anastomosis, we often refer to the structure whose end is anastomosed as the "graft vessel" while the structure whose side wall is anastomosed is referred to as the "receiving structure".
Anastomotic material typically includes autologous material, but it can also include heterologous material or synthetic material. An autologous graft is a graft in which the donor and recipient areas are in the same individual. Heterologous material is derived from an animal of a different species. The graft can be made of a synthetic material such as expanded polytetrafluoroethylene ("ePTFE"). Wolf Dieter Brittinger, Gottfried Walker, Wolf-Dieter Twittenhoff, and Norbert Konrad, Vascular Access for Hemodialysis in Children, Pediatric Nephrology, Vol. 11 (1997) pp. 87-95. When both ends of the graft are attached to a receiving structure, the configuration of the receiving structure with the anastomosed graft is called a bypass.
Depending on the anastomotic cross-section, anastomoses are termed bevelled or circular. In a bevelled anastomosis, the structures are joined in an oblique fashion, whereas in a circular anastomosis the structures are joined in a plane that is vertical with respect to the ultimate flow through the structures.
A nonocclusive anastomosis is typically an end-to-side anastomosis in which the flow of matter through the vessel that is anastomosed in its side is not interrupted while the anastomosis is performed. Most conventional techniques for vascular anastomosis require the interruption of blood flow through the receiving vessel while the anastomosis is performed.
Although the parts of a blood vessel are designated by well-known terms in the art, a few of these parts are briefly characterized here for introducing basic terminology. A blood vessel is in essence a tubular structure. In general, the region comprised within tubular walls, such as those defining a blood vessel or the walls defining the tubular member of an endoscope, is termed the lumen or the intraluminal space. A lumen that is not occluded is a patent lumen and the higher the patency of a blood vessel, the less disrupted the blood flow through such vessel is. A reduction of a blood vessel's patency can be caused by a stenosis, which is generally a stricture or narrowing of the blood vessel's lumen. A hyperplasia, or tissue growth, can also reduce a blood vessel's patency. Reduction of blood vessel patency, and in general a disruption in a vessel's blood flow, can lead to ischemia, which is a local lack of oxygen in tissue due to a mechanical obstruction of the blood supply.
A stent is a device that can be used within the lumen of tubular structures to assure patency of an intact but contracted lumen. Placement of a stent within an occluded blood vessel is one way of performing an angioplasty, which is an operation for enlarging a narrowed vascular lumen. Angioplasty and bypass are different ways for reestablishing blood supply, an operation that is called revascularization.
A blood vessel is composed of three distinct layers. From inside to outside, these layers include the intima, the media and the adventitia. The intima is a single layer of flat cells that collectively line the lumen. The media is a thick middle layer composed of smooth muscle cells. The adventitia is an outer layer that comprises fibrous covering.
Angiography is a technique for performing a radiography of vessels after the injection of a radio-opaque contrast material. This technique usually requires percutaneous injection of a radio-opaque catheter and positioning under fluoroscopic control. An angiogram is a radiograph obtained by angiography. Fluoroscopy is an examination technique with an apparatus, the fluoroscope, that renders visible the patterns of X-rays which have passed through a body under examination.
2.2 Related Technology
The operative union of two hollow or tubular structures requires that the anastomosis be tight with respect to the flow of matter through such structures and also that the anastomosed structures remain patent for allowing an uninterrupted flow of matter therethrough. For example, anastomosed blood vessels should not leak at the anastomosis site, the anastomotic devices should not significantly disrupt the flow of blood, and the anastomosis itself should not cause a biological reaction that could lead to an obstruction of the anastomosed blood vessels. In particular, anastomosed blood vessels should remain patent and they should ideally not develop hyperplasia, thrombosis, spasms or arteriosclerosis.
Because anastomosed structures are composed of tissues that are susceptible to damage, the anastomosis should furthermore not be significantly detrimental to the integrity of these tissues. For example, injury to endothelial tissue and exposure of subintimal connective tissue should be minimized or even eliminated in vascular anastomosis.
Because structures to be anastomosed are internal, an anastomosis requires a degree of invasion. The invasive character of an anastomosis, however, should be minimized subject to the reliable performance of a satisfactory anastomosis. Accordingly, there has been a noticeable trend during the last quarter of this century towards less invasive surgical intervention, a surgical style that is termed minimally invasive surgery. This style is characterized by pursuing a maximal treatment effect with minimal damage to surrounding and overlying normal structures. In addition, successful minimally invasive procedures should procure patency and they should minimize damage to the tissues of the anastomosed structures themselves.
A plurality of factors provide a propitious environment for this trend towards minimally invasive surgery. These factors include the development of high-technology diagnostic devices, the innate characteristics of human psychology and economic imperatives.
High-technology diagnostic devices such as flexible fiber-optic endoscopes and intravascular catheters have considerably enhanced our ability for performing a reliable spacio-temporal location of disease. More specifically, these devices permit the early and accurate determination of disease processes and their loci. Furthermore, it is known that the earlier a tumor or growth can be identified, the more responsive it is to therapy by a minimally invasive technique. See Rodney Perkins, Lasers in Medicine in Lasers--Invention to Application, edited by John R. Whinnery, Jesse H. Ausubel, and H. Dale Langford, p. 104, National Academy of Engineering, National Academy Press, Washington, D.C. 1987. (This work will hereinafter be referred to as "Lasers--Invention to Application"). See also Edward R. Stephenson, Sachin Sankholkar, Christopher T. Ducko, and Ralph J. Damiano, Robotically Assisted Microsurgery for Endoscopic Coronary Artery Bypass Grafting, Annals of Thoracic Surgery, Vol. 66 (1998) p. 1064. (This article will hereinafter be referred to as "Endoscopic Coronary Artery Bypass Grafting").
Human psychology also contributes to the growing trend towards minimally invasive techniques. This is attributed to the accepted prevailing preference of a minimally invasive technique with respect to a more invasive surgical technique whenever the outcomes of these two techniques are equivalent.
Finally, minimally invasive techniques are generally cost effective to insurers and to society in general because they are performed on an outpatient basis or else they require comparatively shorter hospitalization time. Furthermore, the less tissue is invasively effected in a procedure, the more likely it is that the patient will recover in a comparatively shorter period of time with lower cost hospitalization. Therefore, economic factors also favor the development of minimally invasive techniques because they can be performed with lower morbidity risk and they satisfy economic imperatives such as reduced cost and reduced loss of productive time. See Rodney Perkins in Lasers--Invention to Application, p. 104; Endoscopic Coronary Artery Bypass Grafting, pp. 1064, 1067.
Particularly in the field of vascular anastomosis, it is acknowledged that there is an increasing demand for an easier, quicker, less damaging, but reliable procedure to create vascular anastomosis. This demand is further revitalized by the movement of vascular procedures towards minimally invasive procedures. See Paul M. N. Werker and Moshe Kon, Review of Facilitated Approaches to Vascular Anastomosis Surgery, Annals of Thoracic Surgery, Vol. 63 (1997) pp. S122-S127. (This work will hereinafter be referred to as "Review of Facilitated Approaches to Vascular Anastomosis").
Conventional exploration and anastomosis techniques are not always implemented in such a way as to satisfy the demand for an easier, quicker, less damaging, but reliable vascular anastomosis. The following overview of conventional exploration and anastomosis techniques closes this background section on related technology.
Exploration of a blood vessel typically provides necessary information for locating and diagnosing vascular abnormalities such as those that reduce vascular patency. This exploration is usually performed with angiography, a procedure that detects vascular abnormalities fluoroscopically. When it is concluded that the appropriate corrective action requires an anastomosis, conventional procedures ordinarily follow a sequence in which the anastomosis is not performed at the time when the initial exploration and diagnostic are performed, but at a later time and in a typically different clinical setup. Accordingly, the time and resources that are spent during the exploration and diagnostic phases are not directly employed in the performance of an appropriate corrective action, such as an anastomosis.
By performing an anastomosis considerably after the initial exploration has taken place and in a different location and clinical environment, these conventional procedures also waste a significant part of the information acquired at the exploration phase. Images obtained during an angiographic procedure are typically recorded on film or digital medium. In current clinical practice, these recorded images are reviewed in a subsequent clinical setting and based upon a knowledge of external anatomy, the lesion location and optimal site for anastomosis are estimated. This process sacrifices potentially useful information. Fluoroscopic visualization is no longer available without repeating the angiogram procedure, and in conventional practice external anatomic localization is used in correlation with previously recorded images. In addition to this external inspection, conventional procedures could rely on imaging for determining the optimal anastomosis site when corrective action is taken. However, having to reacquire information leads to a waste of resources, it significantly increases the period of time from exploration to corrective action, it is an additional burden on the patient, and it enhances the invasive character of the treatment that is administered to the patient. Furthermore, reacquisition of information might have to be done in an environment that demands higher skills and more resources than they would have been otherwise needed. For example, the opening of a body cavity to expose the anatomical region around a potential anastomosis site, the determination of the optimal anastomosis site by external inspection, and the surgical performance of the anastomosis are part of a treatment that is more complex, requires practitioners with more training, and may be more time and resource consuming than the treatment provided by the methods, systems and apparatuses of the present invention.
Vascular anastomosis techniques can be classified in a plurality of groups. Although with various degrees of success, all these techniques generally intend to provide leak-proof joints that are not susceptible to mechanical failure, and they also intend to minimize damage and reduce the undesirable effects of certain operational features that may lead to post-anastomosis complications. Damage to be minimized and operational features whose undesirable effects should be reduced include endothelial coverage injury, exposure of subintimal connective tissue, exposure of an intraluminal foreign component, blood flow interruption, irregularities at the junction, adventitial tissue stripping, intimal injury, installment of a foreign rigid body, use of materials that may have toxic effects, damage to surrounding tissue, extensive vessel eversion, and tissue plane malalignment. Post-anastomosis complications include intimal hyperplasia, atherosclerosis, thrombosis, stenosis, tissue necrosis, vascular wall thinning, and aneurism formation. In addition, vascular anastomosis techniques are characterized by varying abilities to successfully cope with the dilating character of the structures to be anastomosed, their diversity in size, and the possibility that at least one structure may grow after the anastomosis has been performed. Other variables that partially determine the suitability of a specific anastomosis technique include the nature of the material to be anastomosed (for example, autologous, heterologous, or synthetic), the desired reduction in operative time, the skill requirements, and the healing time.
Each one of the techniques discussed hereinbelow for joining anastomosed structures presents a compromise for reducing undesirable effects in the practice of vascular anastomosis. High standards in one or a few aspects of the anastomosis can sometimes be achieved only at the expense of sacrificing what otherwise would have been the benefits of other aspects of the anastomosis.
Since early in the 20th century when vessel anastomoses were performed with an acceptable degree of reliability, the standard for creation of a vascular anastomosis has been manual suturing. Review of Facilitated Approaches to Vascular Anastomosis, p. S122. Suturing devices and methods are still being developed with the aim at performing less invasive surgical procedures within a body cavity. See, for example, U.S. Pat. No. 5,860,992 disclosing devices and methods for suture placement while performing less invasive procedures.
Regarding the application of sutures in vascular anastomoses, it has been generally reported that "the insertion of transmural stitches, even in experienced hands that employ atraumatic techniques and fine sutures, causes significant damage to the vessel wall. As the result of this the subendothelial matrix becomes exposed to the bloodstream and initiates the formation of a thrombus. The same process takes place at the actual site of the anastomosis in the case of intima-intima apposition. These processes are multifactorial but can cause obstruction of the complete anastomosis, especially in small vessels." Review of Facilitated Approaches to Vascular Anastomosis, p. S122. In addition to proximal occlusion, needle-and-suture-mediated intimal penetration is believed to represent a source of platelet emboli, which can cause distal embolization and thus a hazard in brain revascularization and myocardial circulation. Patrick Nataf, Wolff Kirsch, Arthur C. Hill, Toomas Anton, Yong Hua Zhu, Ramzi Ramadan, Leonardo Lima, Alain Pavie, Christian Cabrol, and Iradj Gandjbakhch, Nonpenetrating Clips for Coronary Anastomosis, Annals of Thoracic Surgery, Vol. 63 (1997) p. S137. (This article will hereinafter be referred to as "Nonpenetrating Clips for Coronary Anastomosis"). Furthermore, it is considered that "suture anastomosis of small vessels is time-consuming and tedious and demands a long and continuous training if high patency rates are to be regularly achieved." Willy D. Boeckx, Oliskevigius Darius, Bert van den hof, and Carlo van Holder, Scanning Electron Microscopic Analysis of the Stapled Microvascular Anastomosis in the Rabbit, Annals of Thoracic Surgery, Vol. 63 (1997) p. S128. (This work will hereinafter be referred to as "Microscopic Analysis of Stapled Microvascular Anastomosis"). In contrast, in all specialties that employ vascular surgery, "there is an increasing demand for a simple, time-saving, but reliable automated, semiautomated, or at least facilitated method to replace the process of manually sutured anastomosis. The most important reason for this demand is the movement of cardiac bypass surgery toward a minimally invasive and possibly even an endoscopic procedure." Review of Facilitated Approaches to Vascular Anastomosis, p. S122. In this respect, improvement "may come from techniques that do not lead to exposure of [a] damaged vessel wall to the bloodstream." Id., p. S122.
Besides the group that includes techniques which rely on suturing, vascular anastomosis techniques can generally be classified in four groups depending on how the tissue is joined and on the type of device or material used for joining the tissue of the anastomosed vessels. These groups are: Stapling and clipping techniques, coupling techniques, pasting techniques, and laser techniques. Id., pp. S122-S127.
2.2.1. Stapling and Clipping Techniques
Although some staplers have been reported as providing leaky joints, a variety of staplers have been developed for end-to-end and for end-to-side anastomosis. U.S. Pat. No. 5,366,462 discloses a method of end-to-side vascular anastomosis. According to this method, the end of the graft blood vessel that is to be anastomosed is everted by 180.degree.; one end of the staple pierces both vessels with punctures exposed to the blood flow and the other end of the staple pierces the outside of the receiving vessel. U.S. Pat. No. 5,732,872 discloses a surgical stapling instrument that comprises an expandable anvil for aiding in the stapling of a 180.degree. everted end of a graft vessel to a receiving vessel. This patent also discloses a stapling instrument for joining the 180.degree. everted second end of a graft vessel whose opposite end has already been anastomosed. To anastomose this second end, this technique requires clearance around the area in which the anastomosis is performed, exposure of the receiving blood vessel, external anatomic identification, and significant external manipulation in the open area around the anastomosis site. U.S. Pat. No. 4,930,674 discloses methods of end-to-end and end-to-side anastomosis and a surgical stapler that comprises a vessel gripping structure for joining the 180.degree. everted end of a graft vessel to another vessel. U.S. Pat. No. 5,695,504 discloses methods and a system for performing an end-to-side vascular anastomosis, where the system is applicable for performing an anastomosis between a vascular graft and the ascending aorta in coronary artery bypass surgery, particularly in port-access coronary artery bypass graft surgery. This system includes a staple with a configuration that combines the functions of an anchor member and a coupling member into a one-piece anastomosis staple. U.S. Pat. No. 5,861,005 discloses an arterial stapling method and device for stapling an opening in an anatomical structure, whether the opening is deliberately formed or accidentally caused. This device employs a balloon catheter that helps positioning the stapling mechanism properly on the organ to be stapled.
Some stapling devices rely on access to the anastomosis area through an opening that might be as big as or comparable to typical openings that are required in surgical procedures. Furthermore, the 180.degree. eversion of vessel ends is viewed as an operation that can be difficult, particularly in sclerotic vessels. Review of Facilitated Approaches to Vascular Anastomosis, p. S123.
In general, clipping techniques rely on arcuate legged clips for achieving a flanged, nonpenetrated, intimal approximation of the anastomosed structures. Reportedly, the use of clips leads to a biologically and technically superior anastomosis as compared to the penetrating microsuture. Review of Facilitated Approaches to Vascular Anastomosis, p. S123. By approximating the everted walls of the two vessels to be anastomosed, a clipping technique avoids stitching and reportedly the subsequent risk of intimal hyperplasia. Gianfranco Lisi, Louis P. Perrault, Philippe Menasche, Alain Bel, Michel Wassef, Jean-Paul Vilaine, and Paul M. Vanhoutte, Nonpenetrating Stapling: A Valuable Alternative to Coronary Anastomoses, Annals of Thoracic Surgery, Vol. 66 (1998) p. 1707. In addition, maintenance of an uninjured endothelial coverage and avoidance of exposure of subintimal connective tissue are considered important features because "regenerated endothelium presents selective dysfunction that may predispose to spasm and atherosclerosis, thereby affecting both medium-term and long-term graft patency" and the risk of thrombosis at the anastomotic site can be reduced. Id., p. 1707.
Nonpenetrating vascular closure staples ("VCS") have been used in anastomoses performed to provide access for dialysis, as well as in kidney and pancreas transplantation. It has been concluded in light of these anastomoses that "the fact that VCS staples are interrupted and do not disrupt the endothelium or have an intraluminal component makes them ideal" for achieving the goals of kidney transplantation. V. E. Papalois, J. Romagnoli, and N. S. Hakim, Use of Vascular Closure Staples in Vascular Access for Dialysis, Kidney and Pancreas Transplantation, International surgery, Vol. 83 (1998) p. 180. These goals include the avoidance of post-operative thrombosis and the avoidance of renal artery stenosis. As with kidney transplants, no anastomotic abnormalities were detected in pancreatic transplants, where the avoidance of arterial stenosis is also very important. Id., p. 180. The results of anastomoses performed for providing vascular access for dialysis were also reported successful. Id., p. 179. In addition, it has been reported that the "VCS applier is easy to manipulate, is as safe as hand-suture methods, and has time saving potential. VCS clips are useful for vascular anastomoses of blood access." Hiroaki Haruguchi, Yoshihiko Nakagawa, Yasuko Uchida, Junichiro Sageshima, Shohei Fuchinoue and Tetsuzo Agishi, Clinical Application of Vascular Closure Staple Clips for Blood Access Surgery, ASAIO Journal, Vol. 44(5) (1998) pp. M562-M564.
In a study of microvascular anastomosis of rabbit carotid arteries, some anastomosis were stapled using non-penetrating 0.9 mm microclips and some anastomosis were conventionally sutured. Arcuate-legged, nonpenetrating titanium clips are applied according to a clipping technique in an interrupted fashion to everted tissue edges at high compressive forces. It is considered that this technique "enables rapid and precise microvascular reconstructions, but requires both training and evertable tissue walls." Nonpenetrating Clips for Coronary Anastomosis, Annals of Thoracic Surgery, p. S135. An example of this clip applier is the VCS device, Autosuture, United States Surgical Corporation, Norwalk, Conn. Nonpenetrating Clips for Coronary Anastomosis, pp. S135-S137. U.S. Pat. No. 5,702,412 discloses a method and devices for performing end-to-side anastomoses where the side wall of one of the structures is cut from the intraluminal space of the graft vessel and the anastomosed structures can be secured by a plurality of clips or by suturing.
It has been concluded that stapled microvascular anastomosis is fast and reliable and histomorphologic examination of the anastomotic site revealed no major differences between sutured and stapled groups. Microscopic Analysis of stapled Microvascular Anastomosis, p. S128. Furthermore, it has also been reported that the "clipped anastomotic technique has a rapid learning curve, the same safety as suture methods, and the potential for facilitating endoscopic vascular reconstruction." Nonpenetrating Clips for Coronary Anastomosis, p. S135. In a study undertaken to compare VCS clips with sutured arterial end-to-end anastomosis in larger vessels, it was concluded that this type of anastomosis "can be performed more rapidly with VCS clips than continuous sutures", and that VCS clips "are potentially useful situations where the clamp time of the vessel is critical." Emmanouil Pikoulis, David Burris, Peter Rhee, Toshiya Nishibe, Ari Leppaniemi, David Wherry and Nonnan Rich, Rapid Arterial Anastomosis with Titanium Clips, The American Journal of Surgery, Vol. 175 (1998) pp. 494-496.
Nevertheless, clipping may lead to irregularities at the junction of the anastomosed vessels. In addition, it has been reported that "both periadventitial tissue stripping and microvascular clip application have deleterious effects in the early postoperative period" and that "temporary clips with a lesser width must be used in place of microvascular clips" while performing microvascular anastomosis. S. Keskil, N. Ceviker, K. Baykaner, O. Uluoglu and Z. S. Ercan, Early Phase Alterations in Endothelium Dependent Vasorelaxation Responses Due to Aneurysm Clip Application and Related Manipulations, Acta Neurochirurgica, Vol. 139(1) (1997) pp. 71-76.
2.2.2. Coupling
Tissue bonding by coupling with the aid of devices such as stents, ferrules, or rings without staples is considered to be older than stapling. Among the more recent devices and techniques, U.S. Pat. No. 4,523,592 discloses anastomotic coupling means capable of end-to-end and end-to-side anastomosis without resorting to suturing. The vessels are coupled with a pair of coupling disc members that cooperatively lock and secure the everted tissue from the anastomosed structures. These everted tissues remain in intima-intima contact with no foreign material exposed to the lumen of the anastomosed vessels. U.S. Pat. Nos. 4,607,637, 4,917,090 and 4,917,091 also disclose the use of anastomosis rings and an instrument for joining vessels or tubular organs which are threaded to the annular devices before the joining. The instrument and the anastomosis rings are shaped and adapted to be utilized mainly in microsurgery. U.S. Pat. Nos. 4,657,019 and 4,917,087 disclose devices, kits and methods for non-suture end-to-end and end-to-side anastomosis of tubular tissue members that employ tubular connection members and provide intima-intima contact at the anastomosis site with no foreign material exposed to the lumen of the vessels being joined. An annuli pair that provides an anastomotic clamp and that is especially adapted for intraluminal disposition is disclosed in U.S. Pat. No. 5,336,233. Because of the intraluminal disposition, this device is exposed to the blood flow in the anastomosed vessels. U.S. Pat. No. 4,907,591 discloses a surgical instrument for use in the installation of an assembly of interlocking coupling members to achieve compression anastomosis of tubular structures. Other coupling devices include the use of intraluminal soluble stents and extraluminal glues, such as cyanoacrylates, for creating nonsuture anastomoses. Reportedly, 98% patency was obtained with these soluble polyvinyl alcohol stents. Review of Facilitated Approaches to Vascular Anastomosis, pp. S124-S125. An absorbable anastomotic device for microvascular surgery relies on the cuffing principle with injection-molding techniques using the polymer polyglactin. Vessel ends that are everted 180.degree. are joined in this technique by an interconnecting collar so that an intima-intima seal is achieved. Reportedly, 96% patency was obtained with these absorbable interconnecting collars. Review of Facilitated Approaches to Vascular Anastomosis, p. S125.
The major advantage of a coupling microvascular anastomotic device has been reported to be the reduction in the time needed for a venous anastomosis, which decreases the total ischemic time. Maisie L. Shindo, Peter D. Constantino, Vincent P. Nalbone, Dale H. Rice and Uttam K. Sinha, Use of a Mechanical Microvascular Anastomotic Device in Head and Neck Free Tissue Transfer, Archives of Otolaryngology--Head & Neck Surgery, Vol. 122(5) (1996) pp.529-532. Although a number of coupling techniques do not place any foreign body in the intraluminal space of the anastomosed vessels, it is considered that the use of a foreign rigid body such as a ring that encloses a dynamically dilating structure is a disadvantage of this type of technique. Furthermore, this type of technique is viewed as not being flexible enough for its application to significant vessel size discrepancies in end-to-side anastomosis, and the devices are characterized as being of limited availability and needed in sets of different sizes. Microscopic Analysis of stapled Microvascular Anastomosis, p. S128. In addition, most coupling techniques require considerable eversion, incisions and mounting of the coupling devices that are difficult or impossible to apply endoscopically.
2.2.3. Adhesives
Pasting by applying adhesives or glues is widely employed in medicine. Several glues have been tested in anastomotic procedures, including fibrin glue, cyanoacrylic glues and photopolymerizable glues.
Fibrin glue is a biological two-component sealant comprising fibrinogen solution and thrombin combined with calcium chloride solution. These components are typically available deep-frozen in preloaded syringes, and they are mixed during application after thawing. Commercially available fibrin glue Tissucol has reportedly been approved by the Food and Drug Administration for use in the United States. See, Thomas Menovsky and Joost de Vries, Use of Fibrin Glue to Protect Tissue During CO.sub.2 Laser Surgery, Laryngoscope Vol. 108 (1998) pp. 1390-1393. This article will hereinafter be referred to as "Fibrin Glue in Laser Surgery."
The use of fibrin glue has been found to be practical in telescoping anastomoses and in microanastomoses. Satoru Saitoh and Yukio Nakatsuchi, Telescoping and Glue Technique in Vein Grafts for Arterial Defects, Plastic and Reconstructive Surgery, Vol. 96(6) (1995) pp. 1401-1408, (this article will hereinafter be referred to as "Telescoping and Glue Technique"); Seung-Kyu Han, Sung-Wook Kim and Woo-Kyung Kim, Microvascular Anastomosis With Minimal Suture and Fibrin Glue: Experimental and Clinical Study, Microsurgery, Vol. 18(5) (1998) pp. 306-311, (this article will hereinafter be referred to as "Microvascular Anastomosis With Minimal Suture and Fibrin Glue"). In contrast, it has been reported that the application of thrombin-based fibrin sealant (fibrin glue) to microvascular anastomoses can have noticeable deleterious effects, particularly when used in venous anastomosis. Christopher A. Marek, Lester R. Amiss, Raymond F. Morgan, William D. Spotnitz and David B. Drake, Acute Thrombogenic Effects of Fibrin Sealant on Microvascular Anastomoses in a Rat Model, Annals of plastic Surgery, Vol. 41(4) (1998) pp. 415-419, (this article will hereinafter be referred to as "Thrombogenic Effects of Fibrin Sealant on Microvascular Anastomoses").
A biological procoagulant solution has been described as promising. The mixture contains bovine microfibrillar collagen and thrombin. Gary Gershony, John M. Brock and Jerry S. Powell, Novel Vascular Sealing Device for Closure of Percutaneous Vascular Access Sites, Catheterization and Cardiovascular Diagnosis, Vol. 45(1) (1998) pp. 82-88; Ted Feldman, Percutaneous vascular Closure: Plugs, Stitches, and Glue, Catheterization and Cardiovascular Diagnosis, Vol. 45(1) (1998) p. 89; Zoltan G. Turi, Plugging the Artery With a Suspension: A Cautious Appraisal, Catheterization and Cardiovascular Diagnosis, Vol. 45(1) (1998) pp. 90-91. (The immediately preceding three publications will hereinafter be referred to collectively as "Novel Vascular Sealing Device").
Cyanoacrylic glues tested on vessels include methyl cyanoacrylate and butyl cyanoacrylate, such as Histoacryl glue (butyl-2-cyanoacrylate). The ultra-violet polymerizable glue polyethyleneglycol 400 diacrylate has also been tested and reported that it "is able to effectively seal vessel puncture sites and anastomotic junctions without acutely augmenting local vascular thrombogenicity." G. A. Dumanian, W. Dascombe, C. Hong, K. Labadie, K. Garrett, A. S. Sawhney, C. P. Pathak, J. A. Hubbell and P. C. Johnson, A new Photopolymerizable Blood Vessel Glue That Seals Human Vessel Anastomoses Without Augmenting Thrombogenicity, Plastic and Reconstructive Surgery, Vol. 95(5) (1995) pp. 901-907, (this article will hereinafter be referred to as "Photopolymerizable Blood Vessel Glue").
Glues used in anastomotic practice face the challenges inherent to factors that include toxicity, thrombogenicity, vascular wall thinning, and mechanical strength of the joint. Review of Facilitated Approaches to Vascular Anastomosis, p. S125; Henk Giele, Histoacryl Glue as a Hemostatic Agent in Microvascular Anastomoses, Plastic and Reconstructive Surgery, Vol. 94(6) (1994) p. 897, (this work will hereinafter be referred to as "Histoacryl Glue as a Hemostatic Agent").
2.2.4. Lasers
Lasers have been used in angioplastic revascularization since about 1984. See for example, Markolf H. Niemz, Laser Tissue Interactions, pp. 216-221, Springer Verlag 1996, (this work will hereinafter be referred to as "Laser Tissue Interactions"); R. Viligiardi, V. Gallucci, R. Pini, R. Salimbeni and S. Galiberti, Excimer Laser Angioplasty in Human Artery Disease, in Laser Systems in Photobiology and Photomedicine, edited by A. N. Chester, S. Martellucci and A. M. Scheggi, pp. 69-72, Plenum Press, New York, 1991, (this work will hereinafter be referred to as "Excimer Laser Angioplasty in Human Artery Disease"); Timothy A. Sanbom, Laser Angioplasty, in Vascular Medicine, edited by Joseph Loscalzo, Mark A. Creager and Victor Brounwald, pp. 771-787, Little Brown Co., (this work will hereinafter be referred to as "Laser Angioplasty"). Whereas balloon angioplasty typically fractures, compresses or displaces plaque material, laser angioplasty typically removes plaque material by vaporizing it. Lawrence I. Deckelbaum, Cardiovascular Applications of Laser Technology, in Laser Surgery and Medicine, edited by Carmen A. Puliafito, pp. 1-27, Wiley-Liss, 1996, (this work will hereinafter be referred to as "Cardiovascular Applications of laser Technology").
The refinement of anastomosis techniques that rely on laser technology has been progressing since the reportedly first use of a neodymium yttrium-aluminum-garnet laser ("Nd-YAG laser") on vascular anastomosis in 1979. Particularly in an end-to-side vascular anastomosis, the end of a graft in the form of a tubular structure is connected to the side wall of a receiving vessel so that the anastomosed end of the graft encompasses the anastomosis fenestra, or artificial window, that has been formed into the side wall of the receiving vessel. Consequently, lasers can be used in anastomoses for welding the anastomosed structures and/or for opening the anastomosis fenestra. In addition to YAG lasers, such as Nd-YAG and Ho-YAG lasers, Excimer, diode, CO.sub.2 and argon lasers have also been used in vascular anastomoses.
Laser welding has been defined as the process of using laser energy to join or bond tissues. Typically, laser welding relies on photothermal effects, but efforts are being made to develop laser welding that relies on photochemical effects, where the laser radiation activates cross-linking agents that are expected to produce stronger links than those produced by photothermal welding. Lawrence S. Bass and Michael R. Treat, Laser Tissue Welding: A Comprehensive Review of Current and Future Clinical Applications, in Laser Surgery and Medicine, edited by Carmen A. Puliafito, pp. 381-415. (This work will hereinafter be referred to as "Laser Tissue Welding").
Generally, the use of lasers in anastomotic practice faces the challenges inherent to factors that include the cost of laser purchase, maintenance and training, radiation damage to surrounding tissue, aneurism formation, the need for about three or four sutures (versus the nine or ten sutures applied in conventional anastomosis), side effects of heat-induced tissue welding, and mechanical failure at the anastomosis site. Review of Facilitated Approaches to Vascular Anastomosis, pp. S125-S126; Laser Tissue Welding, pp. 407-410; Brian C. Cooley, Heat-Induced Tissue Fusion For Microvascular Anastomosis, Microsurgery, Vol 17(4) (1996) pp. 198-208 (this article will hereinafter be referred to as "Heat-Induced Tissue Fusion For Microvascular Anastomosis"). It has been reported, however, that the "nonocclusive Excimer laser-assisted anastomosis technique is safe and yields a high long-term patency rate in neurosurgical patients" and that there might be indications for this method in coronary bypass surgery. Cornelis A. F. Tulleken, Rudolf M. Verdaasdonk, and Hendricus J. Mansvelt Beck, Nonocclusive Excimer Laser-Assisted End-to-Side Anastomosis, Annals of Thoracic Surgery, Vol. 63 (1997) pp. S138-S142. (This article will hereinafter be referred to as "Nonocclusive Excimer Laser-Assisted End-to-Side Anastomosis"). In addition, laser anastomosis is considered to offer moderately reduced operative time, reduced skill requirements, faster healing, ability to grow, and possibly reduced intimal hyperplasia. Laser Tissue Welding, pp. 407-410 (further reporting on selected microvascular anastomosis studies with lasers that include CO.sub.2, argon, and diode lasers). Furthermore, research is being done to replace some of the initial laser sources by other lasers that are believed to be more suitable for clinical applications. For example, recent work with the 980 nm diode laser indicates that it may "replace in the near future laser sources of older conception such as the Nd-YAG." W. Cecchetti, S. Guazzieri, A. Tasca and S. Martellucci, 980 nm High Power Diode Laser in Surgical Applications, in Biomedical Optical Instrumentation and Laser-Assisted Biotechnology, edited by A. M. Verga Scheggi, S. Martellucci, A. N. Chester and R. Pratesi, pp. 227-230, Kluwer Academic Publishers, Dordrecht, The Netherlands, 1996. (This work will hereinafter be referred to as "980 nm High Power Diode Laser in Surgical Applications").
The CO.sub.2 laser can seal blood vessels, including small blood vessels of about 0.5 mm in diameter or less and it has been used in microvascular anastomosis such as in human lympho-venous anastomosis. D. C. Dumitras and D. C. A. Dutu, Surgical Properties and Applications of Sealed-off CO.sub.2 Lasers, in Biomedical Optical Instrumentation and Laser-Assisted Biotechnology, edited by A. M. Verga Scheggi, S. Martellucci, A. N. Chester and R. Pratesi, pp. 231-239, Kluwer Academic Publishers, Dirdrecht, The Netherlands, 1996. (This work will hereinafter be referred to as "Surgical Properties and Applications of Sealed-off CO.sub.2 Lasers"). In addition to the CO.sub.2 laser which is an efficient vaporizer of tissue, other lasers that effectively vaporize tissue include the argon and the KTP/532 lasers. Lasers--Invention to Application, p. 106.
The argon laser has been reported to offer advantages over conventional end-to-end anastomosis procedures applied to growing vessels. Eiji Chikamatsu, Tsunehisa Sakurai, Naomichi Nishikimi, Takashi Yano and Yuji Nimura, Comparison of Laser Vascular Welding, Interrupted Sutures, and Continuous Sutures in Growing Vascular Anastomoses, Lasers in Surgery and Medicine, Vol. 16(1) (1995) pp. 34-40. (This article will hereinafter be referred to as "Comparison of Laser Welding and Sutures in Vascular Anastomoses"). It has also been reported that low temperature argon laser welding limits anastomotic thrombogenicity, which is thought of as a factor that may improve early patency of venous and small arterial bypass grafts. Steven B. Self, Douglas A. Coe and James M. Seeger, Limited Thrombogenicity of low Temperature Laser-Welded Vascular Anastomoses, Lasers in Surgery and Medicine, Vol. 18(3) (1996) pp. 241-247, (this article will hereinafter be referred to as "Low Temperature Laser-Welded Vascular Anastomoses").
The use of lasers for medical purposes requires safety measures for protecting health care practitioners who handle the laser device and for shielding surrounding tissues and avoiding unintended radiation induced damage. Laser shield materials include layers of polymethylmethacrylate and tinfoil. See, Christine C. Nelson, Krystyna A. Pasyk and Gregory L. Dootz, Eye Shield for Patients Undergoing Laser Treatment, American Journal of Ophthalmology Vol. 110 (1990) pp. 39-43. Laser shield materials are known and they have been disclosed in a variety of sources such as Alex Mallow and Leon Chabot, Laser Safety Handbook, Van Nostrand Reinhold Co., New York (1978), and A. Roy Henderson, A Guide to Laser Safety, Chapman & Hall, London (1997). In particular, for example, the biological sealant fibrin glue can prevent severe damage to tissue when accidentally exposed to CO.sub.2 laser radiation and intraoperative coating with fibrin glue can serve as a shield to protect arteries, veins, and nerves from accidental CO.sub.2 laser exposure. Furthermore, it is considered that the use of fibrin glue for laser radiation protective processes "is especially attractive in . . . fields in which the glue is already used for sealing." Fibrin Glue in Laser Surgery at p. 1393.
2.2.5. Other Devices and Techniques
It is known that some anastomosis techniques combine different approaches. For example, biological glues that are based on proteins and other compounds are combined with laser radiation in laser soldering. "Laser soldering is a bonding technique in which a proteinaceous solder material is applied to the surfaces to be joined followed by application of laser light to seal the solder to the tissue surfaces." Laser Tissue Welding, pp. 389-392. Egg albumin, heterologous fibrin glue, and human albumin have been used as laser solders, also known as adjuvant materials for laser tissue welding. Dix P. Poppas, Theodore J. Choma, Christopher T. Rooke, Scott D. Klioze and Steven M. Schlossberg, Preparation of Human Albumin Solder for Laser Tissue Welding, Lasers in Surgery and Medicine, Vol. 13(5) (1993) pp. 577-580, (this article will hereinafter be referred to as "Human Albumin Solder for Laser Tissue Welding").
In an even newer technique, a chromophore is added to the solder to achieve photoenhancement effects that lead to an enhanced light absorption in the solder and not in the nontargeted tissue. Id., p. 391. In laser sealing, also known as laser-activated tissue sealing, sutured or stapled repairs are reinforced with laser solder, which is expected to provide "the strength and security of sutures and the watertightness of solder." Id., pp. 403-404.
The graft in a vascular anastomosis does not necessarily have to be an autologous blood vessel. In addition to ePTFE tubular grafts that have been referred to in a preceding subsection, several synthetic materials for vascular grafts have been used or are being developed.
Synthetic biomaterials that are being developed include polymeric materials with the proteins elastin and fibronectin. A. Maureen Rouhi, Contemporary Biomaterials, Chemical & Engineering News, Vol. 77(3) (1999) pp. 51-63.
ePTFE has been used with a variety of coatings. One type of coating includes fibrin glue that contains fibroblast growth factor type 1 and heparin. John L. Gray, Steven S. Kang, Gregory C. Zenni, Dae Un Kim, Petre I. Kim, Wilson H. Burgess, William Drohan, Jeffrey A. Winkels, Christian C. Haudenschild and Howard P. Greisler, FGF-1 Affixation Stimulates ePTFE Endothelialization without Intimal Hyperplasia, Journal of Surgical Research, Vol. 57(5) (1994) pp. 596-612; Joseph I. Zarge, Vicki Husak, Peter Huang and Howard P. Greisler, Fibrin Glue Containing Fibroblast Growth Factor Type 1 and Heparin Decreases Platelet Deposition, The American Journal of Surgery, Vol. 174(2) (1997) pp. 188-192; Howard P. Greisler, Claire Gosselin, Dewei Ren, Steven S. Kang and Dae Un Kim, Biointeractive Polymers and Tissue Engineered Blood Vessels, Biomaterials, Vol. 17(3) (1996) pp. 329-336. Another coating contains basic fibroblast growth factor in fibrin glue. M. Lanzetta, D. M. Crowe and M. J. Hickey, Fibroblast Growth Factor Pretreatment of 1-mm PTFE Grafts, Microsurgery, Vol. 17(11) (1996) pp. 606-611.
Other grafts comprise a synthetic biodegradable tubular scaffold, such as a vessel made of polyglactin/polyglycolic acid, that has been coated with autologous cells from a tissue culture. Toshiharu Shinoka, Dominique Shum-Tim, Peter X. Ma, Ronn E. Tanel, Noritaka Isogai, Robert Langer, Joseph P. Vacanti and John E. Mayer, Jr., Creation of Viable Pulmonary Artery Autografts Through Tissue Engineering, The Journal of Thoracic and Cardiovascular Surgery, Vol. 115(3) (1998) pp. 536-546.
A common feature of most conventional stapling, coupling and clipping techniques, particularly when applied to small-diameter vessels, is that they require a temporary interruption of the blood stream in the recipient vessel, a disruption that is thought to be not very well tolerated in cardiac bypass surgery. Review of Facilitated Approaches to Vascular Anastomosis, p. S126. In revascularization procedures of the brain, temporary occlusion of a proximal brain artery may cause brain ischemia, and consequently a nonocclusive anastomosis technique is required. Nonocclusive Excimer Laser-Assisted End-to-Side Anastomosis, p. 141. As the instrumentation that is needed at the anastomosis site becomes complex and cumbersome, a wider open area is needed for accessing the anastomosis site, thus leading to an increasingly invasive procedure. Furthermore, conventional anastomosis techniques are usually performed at a site that is determined by external observation of the affected area. This observation is performed at a time and in a medical setup that are different from the time and medical setup of a previous exploratory or diagnosis procedure.
Techniques that require the perforation of blood vessel tissue have raised concerns regarding intimal injury, adventitial stripping, tissue plane malalignment, and anastomotic bleeding. In addition, techniques that rely on devices that are exposed to the blood flow may lead to technical problems associated with a persistent intraluminal foreign body. These factors are thought to "contribute to both early and late anastomotic failure, particularly in the form of neointimal hyperplasia." Nonpenetrating Clips for Coronary Anastomosis, p. S135.
The need for completely endoscopic anastomosis procedures has been clearly expressed in the context of coronary artery bypass grafting. For example, it is currently acknowledged that "the goal of a completely endoscopic coronary artery bypass procedure has not yet been realized, and will require further technological advances." Endoscopic Coronary Artery Bypass Grafting, p. 1064. Furthermore, totally endoscopic coronary artery bypass grafting "is perceived by many as the ultimate surgical model of minimally invasive coronary artery bypass grafting". Hani Shennib, Amr Bastawisy, Michael J. Mack, and Frederic H. Moll, Computer-Assisted Telemanipulation: An Enabling Technology for Endoscopic Coronary Artery Bypass, Annals of Thoracic Surgery, Vol. 66 (1998) p. 1060.
Minimally invasive vascular grafting according to a peripheral procedure is equally desirable, and intraluminally directed minimally invasive active endoscopic or peripheral methods, systems and apparatuses are specially desirable. These methods, systems and apparatuses are specially desirable when, in particular, they are versatile enough as to be able to incorporate a plurality of the desirable features that have been discussed hereinabove while reviewing different groups of vascular anastomosis techniques. This desirability is consistent with the reported expectation that reliable methods for facilitated anastomosing of vessels will be developed by combining the best features of a variety of techniques. Review of Facilitated Approaches to Vascular Anastomosis, p. S126.
Each one of the afore-mentioned patents and publications is hereby incorporated by reference in its entirety for the material disclosed therein.